Ivan Nova has become a chicken-or-the-egg situation in the Yankees clubhouse. He hasn’t lost a game since June 3, and after 15 consecutive winnings decisions, the soft-spoken, sometimes erratic guy who showed up in 2010 has been replaced by a confident, consistent winner who seems here to stay.

“If you ask me, who is the best pitcher in the world, I say me,” Nova said. “You have to believe that. That’s why you win so many games.”

So which came first, the confidence or the wins? Or did they both build over time?

“It’s easy to throw strikes and stay in a groove when everything is going your way,” Joe Girardi said. “When things aren’t going your way, are you able to correct it? For me that’s the toughest thing for pitchers. He has found a way to get that done.”

During my last year covering Triple-A ball, Nova was a second-half call-up from Double-A. Despite unimpressive Triple-A numbers that year, he had a confidence bordering on cocky. Now that same attitude is starting to show at the big league level. And that’s a good thing. Nova’s learned to limit the damage — something he couldn’t do in 2010 — and he doesn’t let winnable games slip away. He seems to believe he’ll get out of trouble and get away with a win.

“He’s a monster,” Alex Rodriguez said. “I don’t know when people are going to realize that. He is a fantastic pitcher. He has four-plus pitches. All four pitches are above major league average. And his velocity, he threw a pitch today that was 96. All he knows how to do is win. He’s very composed. He works extremely hard. And he’s turning the corner, big time.”

He’s pitching like a guy who got around that corner a long time ago.

“Every time I win, like I win today, I can’t wait until my next start to try to win again,” Nova said. “It feels special. When you win, you make a lot of people happy, especially my family. I like to make my family happy. If I can win all the time, it’s got to feel really good.”

• From the Yankees, Andy Pettitte’s pitching line in an extended spring training game against the Pirates: 5 IP, 4 H, 2 ER, 0 BB, 5 K. He threw 66 pitches, 58 strikes. The Associated Press reported 5.2 innings for Pettitte — given that it’s extended spring, there’s a solid chance some of those innings went four or five outs just to get his pitch count up — and Pettitte told the AP that he expects to make his next start at a higher classification, likely Double-A.

• On a day that was supposed to celebrate the Red Sox history, Derek Jeter moved past Dave Winfield on baseball’s all-time hits list and Alex Rodriguez moved past Ken Griffey Jr. on the all-time home runs list. Up next for Jeter is Tony Gwynn, 30 hits away. Up next for Rodriguez is Willie Mays, 29 homers away. “When the time comes, that’s a pretty great name,” Rodriguez said.

• Eric Chavez came into this game with six at-bats this season. His first two at-bats of the day were both home runs. He hit two homers all of last year. “I didn’t get a lot of at-bats prior to this, so you just do the best you can,” Chavez said. “I try to take as many swings as I can in the cage during the game at home. Try to do the best you can when you get the opportunity.”

• Russell Martin didn’t have an extra-base hit this season before crushing a home run off the sports authority sign at the top of the Green Monster. “I’ve been telling you that his at-bats have been better,” Girardi said. “He has taken his walks. It was a little mechanical thing. He hit two balls right on the screws today.”

• Girardi put Cody Eppley into the ninth inning because he was hoping to avoid using Mariano Rivera, but he had already decided to bring in Rivera if anyone got on base. “You give him some wiggle room,” Girardi said. “This park can be difficult sometimes. The wind is blowing out today so I made sure I gave him some wiggle room.”

• Girardi had multiple in-game conversations with the umpire crew seeking a rule clarification about the left field wall. One of the ball-strike indicator lights on the Monster was missing, and Girardi was worried that a hit ball might go into the hole. “I know the chances are really, really, really slim that that’s going to happen,” he said. “But I sure would hate to lose a game because of that.” The umpires decided it would be a ground-rule double.

• The Yankees actually seemed to love their one-time-only throwback uniforms. Girardi said they were more comfortable than the regular uniforms.

• I actually loved the pregame ceremony. I thought the Red Sox did a nice job. “I was out there at 2, man,” Nick Swisher said. “I thought it was absolutely awesome. Bringing all the greats that came back that have made this franchise what they are. Whether you’re a Red Sox fan or you’re not, I’m a baseball fan. To be able to go out there and see all those guys coming out, the ovations all those guys were getting, it was great. What a great day for baseball. … We come out to win the game. I don’t care where we’re playing or who we’re playing, we go out there to win. Today was our day.”